The widely visible ducal residence castle is an outstanding example of architecture between the Renaissance and Baroque periods. With its uniquely tall structure in Schleswig-Holstein, castle-hill from the baroque period, and 19th century palace garden, the castle offers a beautiful view of Plön Lake. The castle was renovated in January 2002 after the non-profit Fielmann Academy purchased it from the local government. Since 2005, the Fielmann Academy has used the space as a public education center for the training of optometrists. In addition to these changes, visitors now have access to many rooms that were previously unavailable: the restored chapel, the ducal residence, and the knight’s hall. The castle has undergone only historically accurate reconstruction and will be visible for the first time for the concerts of the 2007 Schleswig-Holstein Musik Festival.